Paper feeding devices



M mini April 26, 1960 R. A. DAVIS ET @L 2,934,339

PAPER FEEDING DEVICES Filed April 29. 1958 INVENTORJ Foes/v fi/Pr/w/e 0/9 v/y 19.4 H /P086397 HEW/fr MMMW ATTORNEYS mechanisms are not satisfactory at these speeds.

, from the rest position.

United States Patent C 2,934,339 PAPER FEEDING nnvrcns Roger Arthur Davis and Alan Robert Hewitt, Letchworth, England, assignors to International Computers and Tabulators Limited, London, England Application April 29, 1958, Serial No. 731,726 Claims priority, application Great Britain May 6, 1957 14 Claims. (Cl. 2712.4)

The invention relates to paper feeding apparatus for data printing machines and the like.

In machines for printing lines of characters on webs of paper, paper feeding mechanisms are used to advance the so that each line of characters is correctly positioned on the web. Hitherto such mechanisms have been required to operate only two or three times in a second, and clutch controlled devices for this purpose, using one revolution clutches, are well known.

In high speed printing machines paper feeding mechainsms may be required to operate as many as twenty times in a second, and it has been found that the known The difficulties experienced at high speed appear to be caused principally by two factors; conventional mechanical clutch mechanisms require an appreciable time for engagement and the inertia of moving parts of the paper feeding mechanism operated at high speed causes overthrow .with the result that accurate alignment of the paper at a predetermined printing position is not achieved.

It is an object of the present invention to provide an improved paper feeding mechanism which feeds paper to a predetermined line position.

It is a further object of the invention to provide means for reducing the overthrow of high speed paper feeding means to ensure accurate alignment of the paper at a predetermined position.

According to one feature of the invention paper feeding apparatus comprises a continuously rotating input shaft, an output shaft, paper feeding members adapted to be driven by the output shaft, a friction clutch adapted normally to couple together the input and output shafts, selectively operable stop means adapted to declutch the friction clutch to stop the output shaft in any one of two or more rest positions and to retain the output shaft 'against rotation in one direction and locating means shaft, a helical spring adapted normally to frictionally engage both clutch members to transmit the drive from the input to the output shaft, selectively operable stop means adapted to disengage the spring from the clutch members to stop the output shaft in any one of two or more rest positions and to retain the output shaft against rotation in one direction and locating means adapted to prevent rotation of the output shaft in the other direction According to a further featur e'of the invention" paper feeding apparatus comprises a continuously rotating input 2,934,339 Patented Apr. 26, 1960 shaft, a torsion rod, a friction clutch adapted to couple the input shaft to one end of the torsion rod, paper feeding members adapted to be driven by the other end of the torsion rod, selectively operable stop means adapted to de-clutch the friction clutch to stop the torsion rod in any one of two or more rest positions and to retain said one end of the torsion rod against rotation in one direction, locating means adapted to prevent rotation of said one end of the torsion rod in the other direction from the rest position, and means adapted to allow movement of said other end of the torsion rod in relation to said one end only in the direction in which the rod is driven.

An embodiment of the invention will be described, by way of example, with reference to the accompanying drawing in which:

Figure l is a part sectional view of the paper feeding drive mechanism, and

Figure 2 shows an alternative view of the clutch mechanism.

The feeding mechanism is supported between side plates 1 (Figure l), and is driven from a continuously revolving input shaft 2, driven in turn, by a motor (not shown). The shaft 2 runs in bearings 3 set in suitable support members 4 of which only one is shown. A bushing 5 is pinned to the shaft 2 and revolves with it. An output shaft 6 (Figures l and 2) is journalled in the plates 1 and the axis of this shaft is in line with that of the driving shaft 2. The shaft 6 carries a pinned bushing 7. One end of the bushing 5 extends over the end of the shaft 6 and abuts one end of the bushing 7. The adjacent ends of the bushings 5 and 7 are the same diameter and form a continuous cylinder around which is wrapped a helical spring 8. This spring is so wound that when it is unstressed it forms a helix of smaller internal diameter than the diameter of the cylinder formed by the ends of the bushings 5 and 7. A pin 9 set in a shoulder of the bushing 7 locates one end of the spring 8, which is unwound sufliciently to allow it to be placed over the cylinder. The spring 8 is wound in such a direction that the rotation of the bushing 5 by the drive shaft tends to tighten the spring on the bushings 5 and'7 so that the drive is transmitted through the bushings to the shaft 6.

. In the drawings the driving shaft 2 tends to turn the shaft 6 in an anticlockwise direction as viewed in Figure 2.

A hollow drum 10 is mounted over the spring 8. The drum carries a pin 11 which locates the second end of the spring 8. On the outer surface of the drum lugs 12 (Figure 2) are formed and each lug is positioned so that it may be engaged by a stop member 13. The engagement of a lug with a stop member prevents the drum 10 from turning in an anticlockwise direction. The pin 11 (Figure l) is therefore in engagement with the lefthand end of the spring 8 and tends to unwind the spring so that the bushing 5 is free to revolve within the spring.

Two slots 15 in the bushing 7 are engaged by projections 14 on the drum 10. Thus whenthe movement of the drum 10 in an anticlockwise direction is arrested, movement of the bushing 7 is also arrested. Any tendency for movement in a clockwise direction due to rebound on the abrupt arresting of thc'drum It) is prevented by 10- cating ratchet wheel 16, secured to the shaft 6, and an associated pawl 17.

The drive is transmitted from the remote end of the shaft 6 through a gear train comprisinggears 18 and 19 to a shaft 20 also journalled in the plates 1. The shaft 20 carries conventional paper driving members in the form of pin wheels 21.

The radial spacing of the lugs 12 is such that each of the drum positions corresponds to the position of a printing line on paper fed by the paper driving members 21. 'The actual spacing-between adjacent printing lines 'is determined by the ratio of the gears 18 and 19.

For the sake of clarity only two stop members 13 are shown, but it is to be understood that as many stop members are provided as there are circumferential lines of lugs 120m the drum. Each such line may ofcourse, conslst of any desired number of lugs. Alternate stop members 13 and their associated operating means are provided on opposite sides of the drum to allow the lateral spacing of the lugs 12 to be less than that required if all stop members were provided on the same side. For this reason alternate stop members are provided with hook ends similar to that referenced 26.

Each stop member 13 is pivoted about a rod 22, and is urged towards the drum 10 by a spring 27 A resetting electromagnet 28 is associated with each member 13 and energisation of the magnet 28 moves the stop member out of engagement with the lug 12. A latch-member 23, pivoted on a rod 24 is urged by a spring 25 intoehgagement with the stop member 13, to retain the-member. 13 in the ineffective position. A latch release electromagnet 29 is associated with each latch member 23 and 'when the magnet 29 is energised the latch member is withdrawn from the stop member 13 so that the drum 10 is brought to rest as the stop member engages the appropriate lug 12.

The operation of the electromagnets 28 and 29 may be initiated by known devices for controlling paper feeding means, for example a punched paper tape may be driven in synchronism with the rotation of the drum 10, and the perforations therein may be sensed to cause the operation of the appropriate electromagnet 29 to stop paper feeding at a predetermined line position. The corresponding electromagnet 28 may be energised at the end of aprinting operation to cause paper feeding to be resumed.

The provision of a number of lugs 12 effectively increases the time available for the operation of the electromagnets 29. For example, in order to cause the paper to move a distance equal to one line of'printing, it is not necessary to operate a magnet 29 in the time taken for the passage of one line past the printing position. If the drum is brought to rest in the position shown in Figure 2 by the action of the left-hand stop member the magnet 29 associated with the next adjacent member may be energised while the drum 10 is stationary. This latter stop member then drops to its operative position and is ready to arrest the drum after it has been released by the restoration of the left-hand stop member 13. The movement of the drum is then equivalent to one line space.

When the driven shaft 6 is at rest, the pawl 17 is engaged with one of the notches 30 in the ratchet wheel 16. This restrains the shaft 6 from turning in a clockwise direction under the influence of the helical spring 8 acting on the pin 9 in the bushing 7. A notch 30 is provided corresponding to each lug 12. The projections 14 on the drum 10 are smaller than the slots 15 in the bushing 7. Thus, when the drum is stationary and the pawl 17 is engaged in a slot of the ratchet wheel, one edge of each of the slots 15 engages one edge of each of the projections 14 and holds the drums so that one lug 12 is in contact with a stop member 13. In this position the pins 9 and 11 hold the helical spring 8 so that it is unwound sufficiently to allow the bushing to revolve freely.

In order to engage the drive the stop member 13 is -moved away from the drum by the action of the aptightens on the bushings 5 and 7 to drive the shaft 6.

When the drum 10 is next arrested by one of the stop members 13, the drive continues for a short while under the influence of the spring 8,,but since the pin llis now ;stationary the spring is unwound by the action of the pin 9 in the bushing 7, and the drive is disconnected. This .slight .forward drive -together with a small degree of overthrow caused by the inertia of the driven mechanism allows the pawl 17 to drop into a tooth of the ratchet wheel 16, and the driven shaft is again positively located.

It is seen therefore, that the driven shaft is accurately located by the combined action of the pawl 17 and ratchet wheel 16 with the drum 10. 7

The shaft 6 is reduced in diameter for part of its length and the reduced part is' enclosed in a tube 31, which is secured at the driving end in a sleeve member 32 and at the remote end in a sleeve 33. Keyways are provided in the shaft 6 and in the sleeve 33, and a key 34 couples the shaft to the sleeve.

The sleeve member 32 has an internal conical face which co-operates with a cone member .35 secured to the shaft 6. A compression spring 36 is provided at the end of the tube remote-from the driving end and acts between the sleeve 33 and a fixed collar 37 to keep the sleeve-member 32 andv the cone member 35 in engagement.

The sleeve member 32 also has lugs 38.which extend into slots 39 in a driving collar 40 secured to the shaft 6. The drivingcollar is arranged so that the slots 39 have a driving face which normally engages the lugs 38.

The central portion of the shaft 6 is reduced sufficiently toact as a torsion rod. and twisting of the shaft occurs when the paper feeding is stopped suddenly. Any such twisting during feeding of the paper is undersirable and this is prevented by the tube 31. Since the projections 38 are normally in engagement with the driving faces of the slots 39, the loading is largely carried by the tube 31, which is sufliciently rigid to prevent any appreciable twisting.

When the movement of the bushing 7 is stopped abruptly by the engagement of one of the lugs 12 on the drum 10 with a stop member 13, the inertial energy of the gears 18and 19, the shaft 20 etc., and of the moving paper has to be absorbed. This is effected by relative movement occurring between the ends of the shaft 6, this movement taking place against the frictional force produced between the sleeve 38 and the cone 35 by the pressure of the spring 36. The right hand end of the shaft 6, .as seen in Figure 1, tends to continue to rotate, so twisting the central part of the shaft. This, in itself, produces a relatively large force to prevent unrestricted overthrow. However, the tube 31 is rigid, so that any movement of the right hand end of the shaft 6 is transmitted through the tube to the sleeve 32, the slots 39 being wide enough to allow relative movement in this direction between the sleeve 32 and the collar 40. The sleeve 32, pressing on the cone 35, acts as a friction brake to further damp the movement of the right hand end of the shaft 6. As the inertial energy is dissipated, the right hand end of the shaft- 6 and the tube 31 return to the normal position and the paper engaged by the pin wheels clutch formed by the bushings 5 and 7, the spring 8 and the drum 10 is normally engaged, so that drive is transmitted from the shaft 2 to the shaft 20 and paper is being fed. The appropriate magnet 29 is energised to release the associated stop member 13 which is urged into a position-to engage a lug 12 by the spring 27. The magnet 29 merely has to operate the latch 23, so that the spring 27 may be relatively strong to ensure a rapid movement of the stop member 13.

As already explained, the arrangement of the lugs 12 and the stopmembers .13 allowsa considerable tolerance .in the timing of the energisation of the latch release magnets 29. These features, together with the simplicity of the clutch mechanism, combine to provide satisfactory operation at relatively high speeds.

Engagement of a lug 12 with the unlatched stop member 13 stops movement of the drum 10. A slight continued movement of the bushing 7 loosens the spring 8 t dis-engage the drive, and the pawl 17 drops into one of the notches 30 of the ratchet wheel 16. The inertial energy is rapidly absorbed by twisting of the central part of the shaft 6 against the action of the friction brake formed by the sleeve 32 and the cone 35, so that the paper fed by the members 21 is brought rapidly to rest at the required position.

The feed is re-started by energizing the resetting magnet 28 associated with the operated stop member to lift it clear of the drum 1%} and re-engage it with the latch.

This allows the spring 8 to move the drum 1!) until the used to feed the paper between successive positions spaced five inches apart. The rate of feeding was such that the paper was stopped in ten such positions each second. The lugs 12 on the drum were positioned to provide a minimum spacing of A; of an inch between adjacent stopping positions of the paper.

We claim:

1. Paper feeding apparatus comprising a continuously rotating input shaft, a torsion rod, a friction clutch coupling the'input shaft to one end of the torsion rod, paper feeding members driven from the other end'of the torsion rod, stop means selectively operable to tie-clutch, the friction clutch to stop the torsion rod in any one of at least two rest positions and operative to retain said one end of the torsion rod against rotation in one direction, locating means operable to prevent rotation of said one end of the torsion rod in the other direction from the rest position, and means permitting movement of said other end of the torsion rod in relation to saidone end only in the direction in which the rod is driven.

2. Apparatus as claimed in claim 1, in which the means for restricting relative movement between the ends of the torsion rod includes a rigid tube coupled to said one end of the rod to allow relative rotation in one direction and coupled to said other end of the rod in such a way 'on relative movement between the ends of the rod.

4. Apparatus as claimed in claim 3, in which said one end of the torsion rod has secured to it a first member with radial slots and a second member with a conical surface and in which the tube has secured to it a sleeve with projections and an internal conical surface; said spring holding the tube in a position in which the two conical surfaces are in contact and the projections lie within the slots.

5. Apparatus as claimed in claim 1, in which said friction clutch comprises a first clutch member secured to the input shaft and a second clutch member coupled to said one end of the torsion rod and a helical spring surrounding, and normally in frictional contact with part of each clutch member, and in which said stop means is adapted to disengage said spring from said clutch members.

6. Apparatus as claimed in claim 5, in which the stop means includes a drum mounted concentrically with the helical spring and engaging the clutch member on said torsion rod, one end of the helical spring being retained by the drum, and the other end of the spring being retained by the clutch member on said torsion rod.

7. Apparatus as claimed in claim 6, in which the drum has at least one projection which engages one face of a slot in the said clutch member when the clutch is engaged and the opposite face of the slot when the clutch is dis engaged.

8. Apparatus as claimed in claim 7, in which the drum has at least two projecting lugs lying on the same circumferential line and in which a stop member is normally held in a latched position out of engagement with the lugs and is releasable to engage one of the lugs under control of an electromagnet.

9. Apparatus as claimed in claim 7, in which the drum has a number of projecting lugs lying on two or more circumferential lines and in which there is a stop member associated with each circumferential line of lugs, each stop member being normally held in a latched position out of engagement with the lugs and being releasable to engage one of the associated lugs under control of an electromagnet.

10. Apparatus as claimed in claim 8, in which a released stop member is urged into engagement with a lug by a spring.

11. Apparatus as claimed in claim 10, in which a re ber resiliently coupling the intermediate and output shafts,

selectively operable stop means operable to stop the intermediate shaft in any one of a number of rest positions and to prevent rotation of the intermediate shaft in said one direction from a rest position, and locating means operative to prevent rotation of the intermediate shaft in the opposite direction from a rest position, whereby movement of the paper feeding means is controlled by said second coupling member when the intermediate shaft is arrested by the stop means.

13. Paper feeding apparatus as claimed in claim 12, having means operative to produce a frictional braking force on relative rotational movement between the intermediate and output shafts.

14. Paper feeding apparatus as claimed in claim 12, in which the stop means includes a drum mounted on the intermediate shaft, circumferential lines of projections on the drum, a lever for each line of projections, and electromagnetic control means operable to move the lever to a first position in which it lies in the path of the associated line of projections and to a second position in which the lever is clear of the path.

References Cited in the file of this patent UNITED STATES PATENTS 

